ABSTRACT- Research, development and application of nanotechnology are accelerating world-wide in several major sectors including health, manufacturing, defense and energy. It is likely that this will soon result in rapid and widespread introduction of manufactured nanomaterials into commerce. Experience tells us that any chemical, physical or biological substance that is widespread in commerce will become widespread in the environment which will ultimately result in human and ecological exposures. Despite the rapid advance of nanotechnology and the corresponding large and growing investments in research and development, risk related research in this field of study is almost completely lacking. Before we can quantitatively evaluate potential risks associated with nanomaterials, there is a need for fundamental understanding of potential release scenarios and subsequent behavior of nanomaterials, both in the environment and in organisms. In this paper we illustrate how we can draw on our experience with conventional organic and inorganic pollutants as a starting point for developing bounding estimates of likely environmental fate and exposure outcomes for new materials. Our goal is to identify methods and conceptual models along with simple hazard metrics that can be used in a prospective application to evaluate the potential environmental, ecological and human-health impacts of manufactured nanomaterials. We use the existing repository of information and models that have been developed for conventional chemical pollutants as a starting point to identify research priorities for different types of manufactured nanomaterials. We consider data needs and requirements for both hazard assessment and risk assessment for environmental, ecological and human health endpoints. Although this type of prospective analysis cannot be validated it does provide a testing ground for identifying conditions that might present a concern and that warrant closer consideration.